This invention relates to a temporary stent catheter for use within a body passageway or duct and more particularly to the use of a temporary stent for restoration of patency to arterial lesions following Percutaneous Transluminal Coronary Angioplasty (PTCA).
PTCA is an increasingly accepted treatment for persons suffering from coronary artery disease. However, it does have several disadvantages, one of which is that of acute closure of the coronary artery following the PTCA procedure. By "acute closure" we mean a sudden blockage of blood flow in the coronary artery at the lesion site addressed by the PTCA procedure. This closure is believed to be initiated by cracks, fissures and flaps appearing at the lesion site following the PTCA procedure. In approximately 5-10% of all PTCA procedures, the dissected flaps will either occlude or threaten to occlude the artery. If left untreated, the occlusion can result in ischemia or myocardial infarction.
It has been shown that if these flaps can be pressed against the artery wall for a period of time, they will adhere to the artery wall and the acute or threatened closure will be relieved. PTCA balloon catheters are commonly used in an effort to press the flaps against the artery wall. However, the use of a balloon has the significant disadvantage that the balloon itself occludes the artery being treated and therefore cannot remain inflated in the artery for the period of time necessary to restore patency to the artery.
Reperfusion devices have been developed to press flaps against the artery wall while permitting blood to flow through the artery. For example, the Stack perfusion catheter is an angioplasty balloon that has a lumen through which blood can flow. Also, for example, U.S. Pat. No. 4,585,000 to Hershenson employs a mechanically expanding device provided with a passageway to permit blood flow through the device. However, these devices have the disadvantage that the passageways through the device are small and blood flow can be occluded during prolonged use.
Yet another device for reperfusion is the "Gaspard" catheter in which a braided mesh near the end of a catheter is mechanically expanded to press the flaps against the artery wall. This device permits greater treatment duration since blood is able to flow through the mesh. Similar devices are shown in U.S. Pat. Nos. 4,650,466 to Luther and 4,921,484 to Hillstead. However, these devices generally lack the mechanical strength afforded by a balloon system.
It is therefore an object of the present invention to provide a temporary stent capable of being inserted in a body passageway or duct, expanded to support the passageway or duct, and subsequently removed.
It is also an object of the present invention to provide a temporary stent that will permit the flow of fluids through the portion of the duct or passageway being treated.
It is also an object of the present invention to provide a temporary stent capable of pressing occluding flaps appearing following a PTCA procedure against the arterial wall to restore patency of the artery.